This invention relates to a cutting roller for a mining machine. More particularly, the invention relates to means for dumping dust generated during mining of minerals and to a method of distributing spraying liquid supplied to the cutting roller for dumping the dust.
Conventional cutting rollers for underground mining of the type under discussion include a tubular housing or body, the so-called tube member, on which one or more cutting blades is or are welded so as to extend helically about the tubular housing. Welded on to the outside of the blades at regular intervals are bit holders in which cutter bits are mounted. The end of the cutting roller facing towards the face of the workings is closed off by an end plate.
Cutting rollers of this kind are also known wherein the cutting rollers are provided with a so-called conical closure ring, also known as a conical closure member. This closure ring is fixedly connected to the end plate by welding. The conical closure member is also provided at regular intervals around its outer edge, projecting towards the face of the workings, with bit holders in which cutter bits are mounted, these bits consequently projecting substantially beyond the outer edge region of the conical closure member towards the face of the workings.
Means for spraying liquid around the cutting roller are known in the art. These means involve individual nozzles arranged on the roller. Each spraying nozzle is mounted in the cutter bit so that a spraying liquid jet produced thereby is directed from the cutter bit, which jet cools the bit.
It has been also known in the art to use spraying nozzles for damping or depositing dust generated in the mining process. This, however was not proven effective. Spraying liquid has been supplied to the aforementioned individual nozzles through channels extended within the interior of the cutting roller, which leads to some problems. The installation of individual nozzles in all cutter bits has required many individual channels extended through cutter blades to deliver spraying fluid to the nozzles; this has been found costly and inconvenient. Furthermore, spraying nozzles produced with rather high quality become disturbed by rough working conditions in underground mining and may not only be damaged by a mineral discharged from the workings but can also be damaged at least partially by corrosion. This results in that flowing spraying liquid selects on its way to the nozzles lesser resistance and therefore does not reach all the nozzles. This leads to the fact that the cutting roller is not fully surrounded with spraying liquid; this deteriorates dust damping process. Specifically those nozzles which are mounted at the discharging end of the cutting roller become subject to wear by abrasive mineral after relatively short charging time. In this case all the supply channels are exposed to spraying liquid which under such conditions can leak out. This results in that pressure within the spraying liquid supply system will be reduced so that the function of the majority or all spraying nozzles will worsen and neither proper cooling of cutter bits nor required dust damping will be achieved.
Finally, it is to be noted that spraying liquid consuption in case of the use of individual spraying nozzles is considerable which is undesirable due to high costs of energy at the present time.